[Smolk]

My strategy has always been cover everything with zooms, have primes for the things zooms aren't good at

Interesting and good advice, as I'm actually torn about the same decision (albeit with the 16-50mm PLM thrown in as well). The zooms would also be AW or WR, I don't have any lens that is so far.
But the 31mm would nicely fill up the 21mm - 58mm gap, a range I'd definitely enjoy (32/48/88 equivalence). And it would be perfect for a future FF camera.

That's why I'm considering the 20-40mm as a cheaper zoom that might still do a good job in rainy days and which I could afford together with a used 31mm.
(I have never really relied on any zoom before, the only one I really used was the FA 645 45-85mm, which I sold pretty quickly.)

[UncleVanya]

The 20-40 is surprisingly useful on crop. The range sounds silly small but works better than expected. Moderately wide to moderately tighter than “normal” is pretty useful it turns out.

[Jonathan Mac]

The advantages of the 31mm are (1) FF and film compatibility and (2) speed. I don't think there are any others.

If you don't need either of them then you might as well get rid of it. The 20-40mm is a fine lens.

[normhead]

The advantages of the 31mm are (1) FF and film compatibility and (2) speed. I don't think there are any others.

If you don't need either of them then you might as well get rid of it. The 20-40mm is a fine lens.

The advantage to the 31 is silky smooth transitions and out of focus areas. At a given f/stop even huge lenses like the Sigma 30 1.4 don't match it. It's big lens performance in small portable lens case.

It's dual lens in that it's got creamy smooth transitions and out of focus areas for portraits etc., and yet is quite sharp for landscape edge too edge at ƒ8-16. It's two lenses in one.

SO if someone wants to do a comparison, you might want to look at those features. Not everyone even cares about transition and out of focus areas, they aren't numericized like MTF and CA. But they are among the most important characteristics for producing photos that are easy to look at.

The biggest fault of most reviews is that the one thing every lens should be rated first on, is often ignored altogether. IMHO. Contrast and out of focus rendering should be the first things discussed. MTF sharpness in a low contrast lens doesn't look as sharp as a lens with high contrast and poor out out of focus rendering can ruin any image. The image isn't as pleasing as a lens that might look a little better on an MTF chart. Technical sharpness does not necessarily align with a positive viewing experience. Visual sharpness is what matters.

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Last edited by normhead; 03-17-2022 at 11:09 AM.

[Jonathan Mac]

The advantage to the 31 is silky smooth transitions and out of focus areas. At a given f/stop even huge lenses like the Sigma 30 1.4 don't match it. It's big lens performance in small portable lens case.

It's dual lens in that it's got creamy smooth transitions and out of focus areas for portraits etc., and yet is quite sharp for landscape edge too edge at ƒ8-16. It's two lenses in one.

SO if someone wants to do a comparison, you might want to look at those features. Not everyone even cares about transition and out of focus areas, they aren't numericized like MTF and CA. But they are among the most important characteristics for producing photos that are easy to look at.

The biggest fault of most reviews is that the one thing every lens should be rated first on, is often ignored altogether. IMHO. Contrast and out of focus rendering should be the first things discussed. MTF sharpness in a low contrast lens doesn't look as sharp as a lens with high contrast and poor out out of focus rendering can ruin any image. The image isn't as pleasing as a lens that might look a little better on an MTF chart. Technical sharpness does not necessarily align with a positive viewing experience. Visual sharpness is what matters.

OK, so you're essentially talking about an element of rendering. The 20-40mm also renders very nicely, I wouldn't call it a slouch, of course at f/2.8-4 I wouldn't expect it to have nearly the potential of the 31mm for OOF or transitional rendering.

[normhead]

OK, so you're essentially talking about an element of rendering. The 20-40mm also renders very nicely, I wouldn't call it a slouch, of course at f/2.8-4 I wouldn't expect it to have nearly the potential of the 31mm for OOF or transitional rendering.

Honestly, I think owning them both would be fascinating. This is the first time 2 limiteds could go against each other, although we now have the opportunity to compare the two 21mm ltd. lenses on APS_c, and the 20-40, making 3 lenses in the comparison.

I have the DA 21 ltd. With a DFA 21 ltd. ($1,800) DA 20-40 ($630), so for only $2500, I could do this comparison. And that's with the 20-40 being $370 off at Camera Canada. Never before in the history of Pentax have so many ltd.s been available in the same focal length.

Is it any wonder I don't do many lens comparisons anymore? If you can't afford the lenses you can't do the comparisons. Although Amazon CA has the 20-40 at $599. It's tax return time... hmmm.

Somehow a little over thousand for a good lens kept them interesting, a little over $2,000, not so much.

[mikesbike]

Both of these lenses are very useful and fine-performing in doing what they are best at doing. As usual, it is difficult to make a valid comparison between a good prime lens and a good zoom lens. As usual, the zoom lens will be much more versatile and convenient, and in some cases will enable getting the best shot, since this can be framed quickly and without changing one's location. The prime lens, with its superior aperture capability, will be much better at dealing with low-light situations and at controlling DOF. Most likely, its distortion characteristics will also be better.

[Smolk]

I could get a deal on a 31mm at € 535, so that's on the way now. Still, I need to resolve the AW/WR issue that I have, so at least one lens will come in addition to this.
I would really like to see a comparison with the 20-40mm Ltd and the 16-50mm PLM. I've heard the latter blows the former out of the water - but my own use may vary.

[BigMackCam]

I would really like to see a comparison with the 20-40mm Ltd and the 16-50mm PLM. I've heard the latter blows the former out of the water - but my own use may vary.

It all depends on the assessment criteria, doesn't it? That's the thing with lenses... some folks look for optimal MTF figures edge-to-edge, minimal aberrations / astigmatism / coma etc... whilst others are more concerned with overall rendering. That's why the recent D FA21 Limited has divided opinion to some extent... For some, it's an incredible lens, while for others it's a less appealing proposition. It's really so very personal. It might help if you can define very specifically what's important to you in a lens...

[UncleVanya]

I would really like to see a comparison with the 20-40mm Ltd and the 16-50mm PLM. I've heard the latter blows the former out of the water - but my own use may vary.

They are such different lenses. I don't think the buyer of the 20-40 and the 16-50 are in the same market. Firstly the 20-40 is a limited lens and has that philosophy - smaller, lighter, and jewel-like. The DA* 16-50 is aiming for optical perfection without barriers - it's heavy and large - has a larger range and a constant aperture design. Both are good lenses - the 20-40 is just so dang lightweight and small for what it is. I bought and tried the 18-50 and despite the slightly larger range and smaller package the 20-40 still is more compelling for ME to use. I own the older 16-50 and it rarely gets used but that's probably because I have too many choices.

[mikesbike]

There really is no comparison between the Pentax DA 20-40mm f/2.8-4 Ltd and the DA* 16-50mm f/2.8 PLM because one cannot rationally compare them. I have 2 fast Sigma lenses, the 17-50mm f/2.8 EX DC HSM, and the older FF 24-60mm f/2.8 EX DG screw-driven, and also the Pentax 20-40mm Ltd. Most of the time I choose to have my Pentax 20-40mm Ltd on a KP body. it fits like a custom-made glove, and is remarkably small, lightweight, and beautifully built. A pleasure to carry and use. Imaging is very fine. So the f/2.8 fast lenses are used primarily when I might be in need of the faster aperture. The zoom range is not quite as large, but not drastically so.

If I need plenty of zoom range with very good quality imaging, it's the larger but still-compact Pentax DA 18-135mm without a doubt. These are not competing lenses. Each has its uses to address the circumstances at hand.

---------- Post added 03-21-22 at 05:09 PM ----------

I could get a deal on a 31mm at € 535, so that's on the way now.

If it is in fine condition, you've apparently nailed a very good deal. This is one excellent lens.

---------- Post added 03-21-22 at 05:30 PM ----------

Ultimately I'll be the decider, but I welcome your opinions. I own both these lenses, and I'm starting to test them more thoroughly. But being in hock for my new K-3 lll, I'm strongly considering selling the 31 help pay it off. The 31 Limited is certainly special, even to this "magic lens" skeptic. But the 20-30 seems quite usable in the 25-35mm range on my K-1. It seems to have the same great bokeh, with much less CA and better coatings than the older 31 Limited, plus WR. The 31 is a little smaller, but a little heavier. It won't be much use on my K-3lll, because I have the F series and Takumar 50mm macros near that cropped focal length.

Has anybody else come to this fork in the road? Did you take it?

If you need a great wide/normal fast aperture lens on your APS-C camera body, then you already have it! The FA 31mm Ltd is a great lens. Great for low light scenes and much more. The 50mm lenses are not normal FL on APS-C, but serve for fast aperture moderate tele imaging. Good for portraiture, and more. The DA 20-40mm Ltd is a different animal as a versatile high-quality, very compact but beautifully-made short zoom lens with WR. These lenses do not compete, but serve different purposes. With the DA 20-40mm on my KP, I often carry the amazingly small DA 15mm Ltd and the likewise small DA 70mm Ltd as a small but great kit. The DA 15mm Ltd is so small it lives in the front accessory pocket of my holster-type camera case, and with still room for a spare battery, spare SD card, etc.!!

These are reasons for which we are buying DSLR cameras having the ability to change lenses.

[Smolk]

There really is no comparison between the Pentax DA 20-40mm f/2.8-4 Ltd and the DA* 16-50mm f/2.8 PLM because one cannot rationally compare them.

Which I feared... It is just a difficult choice, in part because I cannot try either locally, to see how they feel in the hand. That's what underpins my question.
I tried to make a large lens heavier by attaching batteries to it (don't ask) but you can't replicate this easily. I have lenses that are heavier for my Rolleiflex 6008, but then that body feels and holds very differently, too (rather good in fact: the weight is more of an issue on my shoulder than in my hands).
Thanks all for responding. I'm somehow hoping some deal comes my way and will help settle the matter

---------- Post added 03-22-2022 at 06:03 AM ----------

It all depends on the assessment criteria, doesn't it?

Indeed... I'm not into absolute sharpness, but the 20-40 got quite a bit of criticism on the Forum review at the 40mm end, which is significant for a small range zoom.
The 16-50 would be a one-lens solution for rainy days. It's not quite Seattle over here, but neither is it Dubai...

---------- Post added 03-22-2022 at 06:05 AM ----------

I don't think the buyer of the 20-40 and the 16-50 are in the same market.

Well, I'm torn between both... one may be much cheaper, but if I feel it doesn't live up to its price, it's money spent.

[jersey]

Unless you need extra sharpness or reach of 16-50 then I think 20-40 will be best choice. It is small, light, a joy to use as it does not get into way. You literally get 4 primes (20, 30, 35, 40) in one set. I often use it this way, setting it up for first shot of the walk and then like an idiot using legs instead of zoom on the lens to get composition. It is that nice. And I never saw any fault on any focal length. Maybe there are but as I said I treat it as if it was a prime so I choose the focal length for composition, and not as zoom in/out function so this may offset any issues this lens may have.

If there is any lens I am in love with it is this. I could live without any other but this. Ok, maybe 15mm Ltd - choosing between 20-40 and 15 will be hard

Here is my album from single in a month and some other pics I got in meantime with 20-40 on K-3 Mk III. Most are shot at night (winter, I hate you) but still plenty of subjects.


HD Pentax-DA 20-40mm f2.8-f4 Limited | Flickr

[UncleVanya]

Well, I'm torn between both... one may be much cheaper, but if I feel it doesn't live up to its price, it's money spent.

If resale is relevant where you are then the risk should be weighted with that in mind. The 20-40 is the cheaper lens so I’d start by acquiring it. If you don’t like it you sell it. Or perhaps renting? Lastly if you can advertise in a social group on the forum (or create one) maybe you can arrange to meet someone relatively local and try their lens.

Flickr and this forum can show you what the lens can do. What it can’t do generally is show you the effort required to get the shots you see. Keeper rates, efforts level in post production, frustration during use… all of that you may need to talk to users directly to gain perspective.

I didn’t buy my copy of the 20-40. I got it when my dad decided he was done with Pentax and traded me his gear for my m43 gear I owned then. It was a lopsided trade but he wouldn’t hear of getting more value. Later I helped him sell off more gear (he switched away from m43 also) and got a lot of m43 gear back! In any case the 20-40 held little appeal for me on paper; I had the 15 and 40; and I had a 16-50/2.8. I just didn’t see the point. Then I used it. There’s something really appealing about this lens - I can’t put my finger on it. I also can’t compare it to the new 16-50 PLM. So eventually you may just have to “bite the bullet” and buy one of these two and try it. Good luck picking! On the positive side, I doubt either one will be a disappointment.

[mikesbike]

Which I feared... It is just a difficult choice, in part because I cannot try either locally, to see how they feel in the hand. That's what underpins my question.
I tried to make a large lens heavier by attaching batteries to it (don't ask) but you can't replicate this easily. I have lenses that are heavier for my Rolleiflex 6008, but then that body feels and holds very differently, too (rather good in fact: the weight is more of an issue on my shoulder than in my hands).
Thanks all for responding. I'm somehow hoping some deal comes my way and will help settle the matter

Well, the DA* 16-50mm f/2.8 PLM is going to feel llike a different animal in terms of handling. But it is designed to be handled, and I'm sure well-designed. Though I've never handled one, I know from experience with other lenses of similar size and weight, although well-designed it is a beast. The DA 20-40mm f/2.8-4 is actually very much the opposite. This beauty is a compact wonder, with lightweight carrying and great handling a big part of its persona. Large and heavy is the price paid for the f/2.8 aperture needed to address certain circumstances and/or needs. it can provide greater shutter speed under the same lighting. This is what it boils down to, and this is why many of us wind up with both types.

You can see for yourself how the DA 20-40mm Ltd lens performs in a visual test by Imaging Resource. They give it a very high rating. Scroll down to the test scene. When you click on it, you will be able to choose from open aperture to smaller aperture. You can choose a section of the scene for a close-up view by clicking on that spot. To get over near an edge, the spot where the top of the paint brush is near the circular graph will give you an idea of sharpness near an edge area. For center, the inner edge of the fabric basket, for example. The images and writing on the bottles provide good evaluations. I can tell you from examining this same test of other lenses, this Pentax lens performs extremely well.

Lenses generally do not perform as well near edges or certainly in corners as well as they do in the central area. This is to be expected. But this lens does better than most. The same for wide open vs. stopped down. This lens does better than most. The same at the extreme FL of a zoom lens. This lens does better than most.

(one heads up is- I discovered in the case of one other lens test done here, the focus of the test shot was obviously out of focus. But that has been very rare among the many lenses I've seen tested here using this same test)

Could the DA* 16-50mm f/2.8 PLM do better at 40mm f/4, especially at edges? Probably- because with this lens that means not wide open and not at its extreme FL. Would it be better at 20mm f/2.8? Probably, since with this lens it is not at its extreme FL. Yet, the DA 20-40mm Ltd performs very well at its extremes, a remarkable accomplishment, and in such a high-quality compact package. So if convenient carrying and handling are a primary concern for you, this one is very hard or impossible to equal. But if you really need that f/2.8 constant aperture throughout, then you have to put up with price/weight/ inconvenience. That very new Pentax PLM lens has not yet faced lab or visual test evaluations.